A short, self-administered questionnaire has been developed and tested that reliably and validly measures frequency and types of dissociative phenomena. This instrument has been administered to a wide variety of psychiatric patient groups as well as normal control subjects and documents a continuum of symptoms of dissociation and depersonalization across these samples. This scale has been adopted by more than 20 research projects around the country and is currently being used by the National Academy of Sciences in a large scale study of posttraumatic stress disorder in Vietnam Veterans.